img 黑白版与彩色版切换

function converttoGS(img) {    img.color = img.src;

    img.grayscale = createGSCanvas(img);    img.onmouseover = function () {        this.src = this.color;    }    img.onmouseout = function () {        this.src = this.grayscale;        alert(this.src)    }}function createGSCanvas(img) {    var canvas = document.createElement(‘canvas‘);    canvas.width = img.width;    canvas.height = img.height;

    var ctx = canvas.getContext(‘2d‘);    ctx.drawImage(img,0,0);

    var c = ctx.getImageData(0,0,img.width,img.height);    for(var i = 0; i <c.height;i++){        for(var j = 0; j<c.width; j++){            var x = (i*4)*c.width+(j*4);            var r = c.data[x];            var g = c.data[x+1];            var b = c.data[x+2];            c.data[x] = c.data[x+1] = c.data[x+2]=(r+g+b)/3;        }    }

    ctx.putImageData(c,0 ,0,0,0,c.width,c.height)    return canvas.toDataURL();}